ClassCastException in Weblogic 5.1 while using OracleCallableStatement

I am using Weblogic 5.1 server and the server creates a connection pool during start up. It was all fine until i decided to pass Arrays to my Oracle Stored Procedures. That required using OracleCallableStatement(in oracle.jdbc.driver).

Am getting a ClassCastException here. If i get the connection directly without using Connection Pooling, there is no problem. These are some of the connection pool relevant entries

I could see that there in one weblogic.jdbc.common.OracleCallableStatement. I dont get an Exception if i cast it to this. But if i use this, am getting a ClassCastException while creating the ArrayDescriptor.

I would be grateful to anyone who could throw some light on this for I've spent the entire day banging my head, ofcourse in vain